FR2644538A1 - TORSIONAL DAMPER, ESPECIALLY DOUBLE DAMPER FLYWHEEL FOR MOTOR VEHICLE - Google Patents

Abstract

The present invention relates to torsion dampers, comprising two coaxial parts 1, 2 mounted to rotate with respect to each other against elastic means with circumferential action comprising at least one elastically deformable arm 13, an internal bearing element 14 and external 15, one of which is linked in rotation by a connection by cooperation of shapes with one of said coaxial parts 1, 2. According to the invention, the other carrier element, called second carrier element, is linked to the other coaxial part, called the second part, by clamping, said second carrier element being subjected to the action of an elastic means with axial action 17, wedged axially on the second part and urging the second carrier element in the direction of a first radial bearing surface 18 presented by the second part for direct or indirect contact with said bearing surface 18. Application: double damping flywheel for a motor vehicle.

Description

264453P

  The present invention relates to torsion damping devices, in particular double steering wheels for a motor vehicle, of the type comprising at least two coaxial parts, rotatably mounted relative to one another within the limits of a determined angular displacement and against elastic means with circumferential action comprising at least one elastically deformable arm and two supporting elements, one internal the other external, said arm extending between the supporting elements with at least one of which it connects with one piece by a rooting zone, one of said support elements being able to be secured in rotation, possibly after catching a circumferential clearance, with one of said rotating parts, while the other of said carrier elements is provided with drive means adapted to rotate it to the other of said rotating parts for

  at least the angular clearance between them.

  Such a device is described for example in the

application FR-A-2 493 446.

  In this there is provided in Figure 22 drive means in the form of a recess by which the elastically deformable arm is engaged with a member integral with one of the rotary parts concerned. This arrangement makes it possible to obtain a connection by cooperation of shapes and promotes an assembly

by axial threading.

  At the level of the internal bearing element, the connection is positive and is made by fitting to

  force, for example using pins.

  The result is the appearance of additional constraints which may be detrimental to the duration of

  life of the shock and its robustness.

  The present invention aims to overcome these disadvantages economically without losing the advantages of an assembly by axial threading on one of the parts of the damper, while providing other advantages. According to the invention, a torsion damper of the aforementioned type, in which one of the carrier elements, said first carrier element, is connected in rotation, possibly with a clearance to one of the coaxial parts, said first part, is characterized in that that the other carrier element, said second carrier element, is connected to the other coaxial part, said second part, by clamping, said second carrier element being subjected to the action of an elastic means axial action axially wedged on said second portion and biasing the second carrier member towards a first radial bearing, which the second portion exhibits, for contact

  directly or indirectly with the said scope.

  Thanks to the invention, there is a connection by cooperation of shapes with one of the parts while obtaining an axial connection by clamping with the other

  part without having to practice expensive machining.

  This arrangement is particularly interesting in the context of a double damping flywheel, as described in document

FR-A-2571461.

  Indeed, the axial connection can be economically part of the torque limiter and, thanks to the invention, it becomes possible to transmit a large torque while having elastic means more

  low stiffness than in the prior art.

  It will be appreciated that in certain arrangements the axial span may be integrated with one of the masses of the double flywheel, so that the reaction plate of the double flywheel can be mounted directly on a bearing interposed radially between said plate and a hub.

solidary of the other mass.

  In addition, the arrangement is space-saving and allows radially to use at best

available space.

  Advantageously, it is possible to provide stops to avoid, in the case in particular of a spiral-shaped leaf spring, that the turns become contiguous when the torque limiter comes into action in order to

arrange said spring.

  The following description illustrates

  the invention, by way of example, with reference to the accompanying drawings in which: - Figure 1 is a half-view in axial section of a first embodiment of the invention; - Figure 2 is a view of the spiral spring, with its limiting stops of the cut travel; - Figures 3 to 6 are views similar to Figure 1 for other embodiments; FIG. 7 is a schematic partial front view for a variant with resilient means of

low stiffness.

  In Figure 1 we see in 1 one of the parts of the double steering wheel for a motor vehicle, or input part, and 2 the other part, or part of the output of

double steering wheel.

  The input portion i is intended to be secured in rotation to the motor shaft of the motor

internal combustion.

  In practice it is fixed to the crankshaft of the engine and one sees in 3 one of the passages of one of the fastening screws (not shown) of the part i to the crankshaft. This part is provided at its outer periphery with a mass 4 carrying a starter ring 5. An annular flange 6 connects the mass 4 to a central hub 7. It is in this hub 7 that the passages of the fixing screws are made. at the crankshaft and the flange 6 is fixed, for example, by countersunk screws to this hub. The mass 4 is fixed here by riveting at this

flange 6 of annular form.

  The outlet portion 2 comprises an annular reaction plate 8. It is on the latter that the friction disc of the clutch, not shown, integral in rotation with the input shaft of the gearbox . This part is secured in rotation by friction of said shaft of the gearbox. The plate 8 surrounds the hub 7 with intervention and radial interposition therebetween a bearing 9, here a bearing, said bearing 9 being mounted in a recessed housing of the plate 8 and the hub-7, being wedged axially by washers 11 attached to said hub 7 and

audit plateau 8.

  The two parts 1, 2 are coaxial and are rotatably mounted relative to each other, within the limits of a determined angular deflection against elastic means with circumferential action 12 comprising at least one elastically deformable arm 13 and two supporting elements 14,15, one internal to the other external, said arm extending between the supporting elements with at least one of which it is connected in one piece by a rooting zone 16, one of the carrier elements, said first carrier element, being adapted to be secured in rotation, possibly after retraction of a circumferential clearance, with one of said coaxial parts, said first part, by a connection

by cooperation of forms.

  According to the invention, the other carrier element, said second carrier element, is connected to the other coaxial part, said second part, by clamping, said second carrier element being subjected to the action of an axial-action elastic means 17, axially wedged on said second portion and urging the second carrier member towards a first radial bearing surface 18, that the second portion presents, for direct contact or

indirectly with said span 18.

  The arm 13 with its supporting elements 14,15

here extends transversely.

  In Figure 1 the elastic means comprise two spiral springs 20, 21 associated in pairs. These springs are obtained by cutting from a metal blank; they are juxtaposed and the corresponding arms 13 work in parallel. Preferably they are arranged head to tail in pairs, one of the blanks of such a pair being returned 180 relative to the other blank of this pair, to avoid a displacement of the center of the assembly in operation due to of the

  deformation of which are the corresponding arms 13.

  These arms 13 are therefore in one piece with the elements

  internal 14 and outer 15 annular carriers.

  In Figure 2 have seen that the connection by form of cooperation consists of teeth and notches, the teeth 23, the inner carrier member 14 of the springs 20,21 cooperating with complementary notches of the plate 8 and vice versa, the teeth alternating with the notches (identified in 23 'at the

Figure 2).

  For forming said connection, the plate 8 has at its inner periphery an axial return 60 in which are machined the teeth and notches common to the

two springs.

  The annular outer bearing member has a reduced thickness at its outer periphery so as to form a shoulder and a housing. This reduction in thickness is symmetrical, the carrier element 15 being notched. It takes advantage of this arrangement to accommodate between the two carrying members an elastic means axial action 17. Here it is a Belleville washer fixed axially on the flange 6 by means of the carrier member 15 of the spring 20 to stressing of the outer bearing member 15 of the spring 21 in the direction of a radial bearing surface 18 of an annular flange 25 directed radially towards the axis of the assembly, which the mass 4 presents for this purpose. The radial extent of the rim 25 is generally equal to that of the thickness portion

reduced by element 15.

  Note that friction washers 24 are interposed, on the one hand, between the flange 6 and the spring

  and, on the other hand, between the spring 21 and the bearing 18.

  They are integral or free with respect to the springs, 21, the washer 17 being interposed axially between

  the carrier elements notched for this purpose.

  Of course the flange 6 offers, vis-à-vis the bearing surface 18, a second radial bearing surface 18 'to the spring, the washer 17 being wedged axially indirectly on the bearing surface 18' for biasing the spring 21 towards the bearing surface 18 A torque limiter is thus formed, the mass 4 forming an axial spacer between

  the two spans 18,18 'parallel to each other.

  The load of the washer 17 is predetermined, as described in the aforementioned document FR-A-2,571,461, to allow sliding at a torque greater than the highest torque of the engine. This occurs in particular when starting the engine and stopping it, the system passing through the frequency

of resonance.

  The calibration of the washer 17 is thus calculated as a function of the maximum torque transmissible by the motor, so that here the friction torque due to the washers 24 is close to said maximum torque, preferably being

superior to this one.

  In order to protect the springs 20, 21 and to prevent the contiguous turns of the latter from coming into contact with them, stop means 26 are provided which limit the movement and the stresses of the springs 20, 21. These are two pions, generally diametrically opposite (FIG. 2) passing axially through the springs 20, 21 through the slots 27 provided therein for forming the arms 13, said slots being enlarged for this purpose in the vicinity of the outer bearing member 15 with shoulder formation 28. One of the shoulders 28 is closed and has a semicircular shape. It delimits the rooting zone 16 of the arm 13. These pins 26 are forced into holes 29 of the reaction plate 8. Thus, in case of over-torque, the angular displacement between the bearing elements 14, 15 is limited by cooperation of the

pins 26 with shoulders 28.

  In normal operation the limiter does not intervene and the arm 13 works, the external carrying element 15, fixed relative to the bearings 18, 18 ', moving angularly with respect to the inner carrying member 14 until the pins 26 come into contact with two of the shoulders 28, shaped accordingly, according to the

sense of relative displacement.

  If the movement continues, in case of overtorque for example, the limiter and the washers 24 intervene, a relative angular displacement of the carrier elements 15 relative to the bearing surfaces 18,18 'occurring, the springs 20,21 remaining bandaged in the state where they are at the pawn cooperation 26

with shoulders 28.

  Of course (Figure 3) the pieces 26 can be

  carried by the flange 6 in one piece with the mass 4.

  In this case the spans 18, 18 ', instead of belonging to the inlet part 1, can belong to the outlet part 2 and the flange 25 carrying the bearing surface 18 consists of a simple washer 40 fixed by riveting to a annular ring 30 of axial orientation from

molding with the tray 8 cast iron.

  The second span 18 'is formed directly on the plate 8 and one sees in 31 one of the fastening rivets

of the washer 40.

  Of course (Figure 4) the outer support member 15 may be rotatably connected to the part 2 by cooperation of shapes & teeth and notches.The plate 8 then has, in the vicinity of the mass 4 in one piece with the flange 6 as in FIG. 3, an axial ring 30 which is provided with an alternation of teeth and notches. The torque limiter is disposed at the level of the inner carrier member 14 and the enlarged portion of the slots 27 delimiting the shoulders 28. One of the bearing surfaces 18 'is formed at the inner periphery of the flange 6 and the other 18 on the hub 7, which then has a radial flange 25 'directed radially away from the axis of the assembly. The pins 26 are integral with the plate 8. Note that the inner carrier member 14 is thinner than the outer carrier member

15.

  Of course (FIG. 5) the structure can be reversed, in this case the torque limiter belongs to the output mass and the pins 26 to the input mass 1, a connection plate 32 forming an axial spacer between the bearings 18, 18 'being necessary, said plate having a flange 25' turned away from the axis of the assembly and being fixed by riveting to the plate 8,

  having at its inner periphery the second span 18 '.

  The mass 4 then has drive teeth and is in one piece with the hub 7 and

the flange 6.

  As is evident from the

  description and drawings, friction pads

  24 of the torque limiter also form spacers, so that all contact is avoided between

  the springs 20,21, the plate 8 and the flange 6.

  No friction also occurs between the springs 20,21 taking into account the mounting clearance and the

spring 17.

  In all cases, the carrier elements concerned are inserted between two annular radial bearing surfaces facing the same part and it is possible to form a subset with these bearing surfaces. This subset

  then goes up by simple axial threading.

  It will also be noted that in FIGS.

  it is possible to test the first part.

  In addition, it is easily possible to lubricate the springs since they are enclosed in a cavity defined by the flange 6, the flywheel 8, the hub 7 which can be made easily sealed with a

  rotary joint and using a sealed bearing 9.

  Of course, the present invention is not

  limited to the examples of achievements described.

  In particular the torsion damper may be a clutch friction, for example the plate 8 being of reduced thickness, like the mass 4, and carrying a friction disc while the hub 7 is grooved to

  rotational connection with a driven shaft.

  The links in rotation between the carrier element and the part of the double flywheel concerned can be

made by splines.

  Only one spiral spring can be provided. In this case the carrier element concerned has on one of its faces a friction lining for contact with the bearing according to the invention and is in contact by its other face an application washer rotatably connected to the relevant part of the double flywheel, the elastic element (FIG. 6) resting directly on the other bearing for urging the application washer towards

  of the aforementioned scope and tightening of the carrier element 15.

  In FIG. 6 (similar to FIG. 3), the applicator washer 50 has engaged tabs 41

in holes 42 of the plate 8.

  The elastic element 17 may consist of a onduflex washer or two Belleville washers mounted in

  opposite direction one above the other.

  It is possible to create a dry friction easily.

  For example, in FIG. 1 it suffices, as described in the document FR-A2 571 461, to use an application washer carrying a friction washer, this applicator washer being linked in rotation to the flange 6 by tabs axial flanges engaged in openings of said flange, a Belleville washer bearing on said flange for biasing said application washer against

  the end of the teeth of the return 60.

  Similarly, the rotational connection by shape cooperation can be performed with clearance. One can even implement elastic means of low stiffness, the teeth and notches having a trapezoidal shape (FIG. 7) and the elastic means of low stiffness 50 of the springs. with coil being mounted in notches 51, springs 20,21, and hub 7, with the intervention of bases 52 at the ends of the springs 50 diametrically

opposed.

  More than two springs 20,21 can be provided. For example, two pairs of elastic blanks can be provided, one of the pairs being flanked by the blanks of the other pair and being angularly offset relative to the other of said pairs, as described in document

FR-88 06 102 filed 6.05.1986.

  One of the supporting elements may not be

continuous and fragmented.

  The spring may have an elastically deformable arm having the shape of that of FIG.

  aforementioned document FR-A-2 493 446.

  The external bearing element is then provided with a recess for cooperation with a projection of the coaxial part concerned and formation of the connection by

form cooperation.

  Each spring 20, 21 may be provided with at least one pair of elastically deformable arms as described.

in US-A-4,795,012.

  Instead of being metallic, the springs may be of synthetic material loaded with reinforcing fibers. In this case, the presence of the washers 24 is not necessarily necessary, these being able to be integrated into the bearing element in question then presenting

an extra thickness for this purpose.

  The carrier element concerned is then, contrary to the embodiments of FIGS. 1 to 6, asymmetrical with on one side an extra thickness for contact with the associated bearing surface and on the other side a

  notch for spring intervention 17.

Claims (8)

  1) Torsion damping device, in particular a double steering wheel for a motor vehicle, of the type comprising at least two coaxial parts (1, 2) rotatably mounted relative to one another within the limits of a determined angular deflection and against elastic means with circumferential action (20,21) comprising at least one elastically deformable arm (13) and two supporting elements (14,15), one external and the other internal, said arm extending between the carrier elements with at least one of which it connects in one piece by a rooting zone (16), one of said carrier elements, said first carrier element being adapted to be secured in rotation, possibly after catching a circumferential clearance, with one of said coaxial parts, said first part, by a connection by cooperation of forms, characterized in that the other carrier element, said second carrier element, is connected to the other coaxial part the said second part, by clamping, the said second bearing element being subjected to the action of an axially acting elastic means (17) axially wedged on the said second coaxial part and urging the said second carrier element towards a first radial bearing (18), which the second part presents, for   direct or indirect contact with said bearing (18).   2) Device according to claim 1, characterized in that said elastic means (17) is wedged axially on a second radial bearing (18 ') of the second portion vis-à-vis the first radial bearing (18). 3) Device according to claim 1 or 2, characterized in that the second carrier element (14,15) is of reduced thickness compared to the first element carrier (15,14).   4) Device according to claim 2 or 3, characterized in that two elastic means with circumferential action (20,21) are provided by being juxtaposed, in that the elastic means with axial action (17) is interposed axially between the second elements carriers of said circumferentially acting resilient means (20,21) for biasing said second bearing members respectively towards the first radial bearing (18) and the second radial bearing (18 '), while the first bearing members are connected by a link by form cooperation to the first part.   ) Device according to claim 4, characterized in that the second bearing elements are entailiés for housing the elastic means to action axial (17).   6) Device according to claim 4 or 5, characterized in that a friction washer (24) intervenes between each radial bearing (18, 18 ') and each second carrier element.   7) Device according to any one of   Claims 4 to 6, characterized in that the means   axial-action elastic member (17) intervenes between the external load-bearing members (15), while the internal-carrying members (14) are connected by shape cooperation with the other coaxial part (12).   8) Device according to any one of   Claims 4 to 6, characterized in that the means   axial-action elastic (17) intervenes between the internal bearing elements (14), while the external bearing elements (15) are connected by shape cooperation with the other coaxial part.   9) Device according to any one of   preceding claims, characterized in that the   first coaxial portion carries abutment means (26) adapted to limit the relative angular displacement between   the internal (14) and outer (15) bearing elements.   ) Device according to claim 9, wherein the plastically deformable arm (13) has a spiral shape, characterized in that the stop means (26) consist of pins (26) passing through the circumferential action elastic means (20). in favor of the slots (27) delimited by the arms, and in that said slots are widened in the vicinity of the second   carrier element for shoulder formation (28).   11) Device according to any one of   preceding claims, characterized in that the   setting of the axial-action resilient means (17) is dimensioned to be close to the maximum torque   transmissible by the engine of the motor vehicle.